This invention relates to an annular end cap structure for closing containers having a cylindrical end or neck.
In particular, the invention relates to reclosable closures of the type in which a rotatable disc or cover member is pivotally connected permanently at the center region of the end cap and can be selectively rotated in sliding face-to-face contact with the end cap to close or unclose openings formed in radially intermediate portions of the end cap--that is, openings formed in portions of the end cap that are radially intermediate the center region and the rim and exclude the center region itself.
A conventional way of providing such an end closure with a rotatable cover member is the provision of a central boss on the cover member received in a central opening in the end closure, as seen for example in La Croce U.S. Pat. No. 3,486,665. This arrangement is simple but does not provide a hermetic seal.
In many such packaging applications, in order to improve shelf life or for other reasons, it is desirable to provide a hermetic seal of the reclosable end cap prior to the first opening thereof. Heretofore, however, no simple means has been provided to accomplish this. Rather, hermetic seals for reclosable end closures which are provided with permanently associated rotary members, pivotally connected at the center of the end cap and intended to close openings at radially intermediate portions, have generally involved rather complex structures such as shown, for example, in Hothersall U.S. Pat. No. 2,094,600.
Hermetic seals have been provided in constructions with rotatable members (not discs) pivotally connected temporarily (not permanently) at the center of an end wall. Such members, however, cannot be reclosed once the hermetic seal is broken on the first opening thereof. An example is Salisbury U.S. Pat. No. 3,281,982.
The present invention provides a reclosable closure construction with a permanently associated rotary member pivotally connected at the center of the end cap and intended to close openings at radially intermediate portions, which compares in simplicity with the most simple prior art constructions such as La Croce, but which provides a hermetic seal that compares in performance to hermetic seal constructions of the prior art such as Hothersall.